NetBSD rev. 1.53, 1.54 and 1.55:   Change how internal boolean variables are used to: 	if ! ${_somevar:-false}; then 		_somevar=true 	fi   (Consisent, slightly quicker, and slightly cleaner)
NetBSD rev. 1.53, 1.54 and 1.55:
  Change how internal boolean variables are used to:
	if ! ${_somevar:-false}; then
		_somevar=true
	fi
  (Consisent, slightly quicker, and slightly cleaner)

Obtained from:	NetBSD

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